1. Field of the Invention
The present invention is related to a lithography system.
2. Background Art
Lithography systems are used to transfer a master pattern onto a substrate using an exposure process. Example lithography systems include, but are not limited to, reflective or transmissive maskless, immersion, and mask-based system. Example substrates include, but are not limited to, semiconductor wafers, flat panel display substrates, flexible substrates, and the like. Light interacting with a static or active pattern generator becomes patterned. This patterned light is projected using a projection optical system onto one or more target areas of the substrate during the exposure process to form features on the substrate.
In a masked-based system, the projection optics often reduce the size of the pattern projected on the substrate by a factor of 4 or more, thus making the mask easier to manufacture and inspect. Lithography systems that utilize patterned masks typically utilize a vacuum clamping device that both holds the mask in place during the exposure process and allows the mask to be quickly released and exchanged for another.
Lithography systems that simultaneous scan both the patterned mask and a substrate during the exposure process utilize stages to accelerate and decelerate the both the patterned mask and the substrate at the start and end of an exposure scan. To achieve higher throughputs, exposing speeds and accelerations have steadily increased to the point where the forces required to accelerate the patterned mask can cause slippage of the patterned mask with respect to the vacuum clamping device. Any unwanted movement of the patterned mask with respect to the substrate during acceleration, or otherwise, can cause errors to features patterned on the substrate.
Therefore, what is needed is a system and method that can be used to substantially reduce or eliminate slippage of a pattern generator with respect to a stage system that controls a position of the pattern generator during a scanning exposure process.